Osteonecrosis
Reviewed: September 2009‎
What Is Osteonecrosis?
Fast Facts: An Easy-to-Read Series of Publications for ‎the Public
Osteonecrosis is a disease caused by reduced blood flow to bones in the ‎joints. With too little blood, the bone starts to die and may break down.‎
Osteonecrosis is also known as:‎
•    Avascular necrosis ‎
•    Aseptic necrosis ‎
•    Ischemic necrosis. ‎
Osteonecrosis is most often found in the hips, knees, shoulders, and ankles. ‎You may have osteonecrosis in one or more bones.‎
In people with healthy bones, new bone is always replacing old bone. This ‎process keeps bones strong and also happens when children grow or if a ‎bone is injured. In osteonecrosis, bone breaks down faster than the body can ‎make enough strong, new bone. If you do not get treatment, the disease ‎worsens and the bones in the joints break down. You may not be able to bend ‎or move the affected joint very well, and you may have pain in the joint.‎
Who Gets Osteonecrosis?
What Causes Osteonecrosis?
What Are the Symptoms of Osteonecrosis?
How Is Osteonecrosis Diagnosed?
How is Osteonecrosis Treated?
What Research Is Being Done to Help People With Osteonecrosis?‎
Who Gets Osteonecrosis?‎
Osteonecrosis can occur in people of any age, but it is most common in ‎people in their thirties, forties, and fifties.‎
What Causes Osteonecrosis?‎
Osteonecrosis is caused when the blood flow to the bone decreases, but why ‎this happens is not always clear. Some known causes of osteonecrosis are:‎
•    Steroid medications ‎
•    Alcohol use ‎
•    Injury ‎
•    Increased pressure inside the bone. ‎
Risk factors for osteonecrosis are:‎
•    Radiation treatment ‎
•    Chemotherapy ‎
•    Kidney and other organ transplants. ‎
Osteonecrosis is more common in people with illnesses such as:‎
•    Cancer ‎
•    Lupus ‎
•    HIV ‎
•    Gaucher’s disease ‎
•    Caisson disease ‎
•    Gout ‎
•    Vasculitis ‎
•    Osteoarthritis ‎
•    Osteoporosis ‎
•    Blood disorders such as sickle cell disease. ‎
Osteonecrosis can also affect people for no known reason, even if they have ‎no other health problems.‎
What Are the Symptoms of Osteonecrosis?‎
When osteonecrosis first begins, you may not have any symptoms. You may ‎start to feel pain when you put weight on a joint with osteonecrosis. As the ‎disease gets worse, you may have more pain and the joint may hurt even ‎when you rest. Pain may be mild or severe.‎
If the bone and joint start to break down, you may have severe pain and not ‎be able to use the joint. For instance, if you have osteonecrosis in the hip, you ‎may not be able to walk. The time from the start of symptoms to losing use of ‎the joint can range from months to more than a year.‎
How Is Osteonecrosis Diagnosed?‎
To diagnose osteonecrosis, your doctor will take your medical history and do ‎a physical exam. Your doctor may then order one or more tests to see which ‎bones are affected:‎
•    X ray ‎
•    Magnetic resonance imaging (MRI) ‎
•    Computed tomography (CT) scan ‎
•    Bone scan ‎
•    Bone biopsy ‎
•    Measure of the pressure inside the bone. ‎
Treatment helps more if the disease is diagnosed early.‎
How is Osteonecrosis Treated?‎
Treatment helps to keep bone in joints from breaking down. Without ‎treatment, most people with the disease will have severe pain and limited ‎movement within 2 years. To decide on the best treatment, your doctor will ‎find out:‎
•    Your age ‎
•    The stage of the disease ‎
•    Where and how much bone has osteonecrosis ‎
•    The cause, if known. If the cause is steroid or alcohol use, treatment ‎may not work unless you stop using those substances. ‎
The goals in treating osteonecrosis are:‎
•    To improve use of the joint ‎
•    To stop further damage ‎
•    To protect bones and joints. ‎
For early stage disease, doctors may first order nonsurgical treatments. If they ‎do not help, surgery may be needed.‎
Nonsurgical treatments
Nonsurgical treatments may relieve pain in the short term, but they do not ‎cure the disease. One or more of these treatments may be used at the same ‎time.‎
•    Medications. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used ‎to reduce pain and swelling. For people with blood clotting problems, ‎blood thinners may be used to prevent clots that block the blood supply ‎to the bone. If you take steroid medications, cholesterol-lowering drugs ‎may be used to reduce fat in the blood. ‎
•    Taking weight off the joint. Your doctor may suggest that you limit your ‎activity or use crutches to take weight off the affected joint. This may ‎slow bone damage and allow some healing. If combined with NSAIDs, ‎it may help you avoid or delay surgery. ‎
•    Range-of-motion exercises. Exercise of the joints with osteonecrosis ‎may help increase their range of motion. ‎
•    Electrical stimulation. Research has shown that this can prompt bone ‎growth. ‎
Surgery
In time, most people with osteonecrosis need surgery. There are four main ‎types of surgery used for osteonecrosis. Your doctor will decide if you need ‎surgery and what type is best for you.‎
•    Core decompression surgery. Lowers pressure inside the bone to ‎increase blood flow to the bone. ‎
•    Osteotomy. Reshapes the bone to reduce stress on the damaged joint. ‎
•    Bone graft. Takes healthy bone from one part of the body and uses it to ‎replace diseased bone. ‎
•    Total joint replacement. Replaces the joint with a manmade one. ‎